Hydrogen bonding in 2-hydroxy((di)thio)benzoates. III. IR and NMR spectra of 2,6-dimethylpiperidinium and tetraethylammonium salts

Solid state ir and solution ir and nmr data are reported for 2,6-dimethylpiperidinium and tetraethylammonium salts of 2-hydroxybenzoic, 2-hydroxythiobenzoic and 2-hydroxydithiobenzoic acid. The solid state ¯v(OH) frequencies, range from 2800 to 2300 cm^–1 and decrease within the series thiocarboxylate (O-HO)>dithiocarboxylate (O-HS)>carboxylate (O-HO)>thiocarboxylate (O-HS), reflect the different kinds of intramolecular O-HY association. The solution ¯v(OH) frequencies range from 2830 to 2560 cm^–1 and decrease within the series thiocarboxylate>dithiocarboxylate>carboxylate; the (OH) proton shifts range from 12.8 to 16.0 ppm and correspondingly increase within the same series. IR and NMR data give confident evidence for an O-HO intramolecular association of the thiocarboxylate anions in solution.     

Crystal and molecular structure of 4-p-hydroxyphenyl-2,2,4-trimethylthiachroman-1,1-dioxide

The title compound1 crystallizes as colorless polyhedra in the monoclinic polar space groupCc, witha=8.107(2),b=21.577(3),c=9.542(2)Å,=103.58(2)°, by contrast with its thioether precursor3, crystals of which have the trigonal space groupR¯3. The structure comprises infinite chains of molecules linked head-to-tail by S=OHO hydrogen bonds of length 2.723(2)Å, with HO contact 1.97(4)Å and O-HO 177(3)°; HÔ=S 146(1)°.     

Polymorphs of nitrofurantoin. 2. Preparation and X-ray crystal structures of two anhydrous forms of nitrofurantoin

The preparation and X-ray crystal structures of two polymorphs of the antibacterial drug nitrofurantoin are reported. The -polymorph is triclinic, space groupP¯1 witha=6.774(1),b=7.795(1),c=9.803(2)Å, =106.68(1),=104.09(2), =92.29(1)°,Z=2. The-polymorph is monoclinic, space groupP2₁/n witha=7.840(5),b=6.486(1),c=18.911(6)Å,=93.17(3)°,Z=4. The nitrofurantoin molecules adopt the same, planar conformation in both polymorphs. Both crystal structures are built up from layers held together by van der Waals forces. In each polymorph, intralayer cohesion is effected by N-HO and C-HO hydrogen bonds, but their arrangements differ in the two crystals. The significance of the C-HO hydrogen bond, now known to occur in four modifications of nitrofurantoin, is discussed.     

Molecular complexes of sulfonamides. 2.1:1 complexes between drug molecules: sulfadimidine-acetylsalicylic acid and sulfadimidine-4-aminosalicylic acid

The preparation and crystal structures of the 1:1 complexes sulfadimidine-acetylsalicylic acid (I) and sulfadimidine-4-aminosalicylic acid (II) are described. Each complex unit is maintained by two intermolecular hydrogen bonds, namely N-HO=C and NH-O, involving the N atom of the sulfonamide group and one pyrimidine N atom of the sulfonamide and the carboxylic group of the acid. Molecular parameters for protonated complexed aspirin, as found in I, are reported for the first time and reveal a significantly different conformation from that of the uncomplexed aspirin molecule. The structure of the 4-aminosalicylic acid molecule does not change significantly on complexation with sulfadimidine. Variation in the hydrogen bonded NO distances in these complexes and their analogs is discussed.     

Crystal and molecular structure of (±)-1-phenyl-2-amino-1-propanol,C9H13NO

The crystal structure of (±)-phenylpropanolamine has been determined by single-crystal X-ray diffraction methods. The structure was solved by direct methods and refined by least-squares toR=0.055 andR _w=0.045 for 2000 reflections (I2 (I)). The molecule was found to adoptgauche geometry. Inter- and intramolecular N-HO and O-HN hydrogen bonds were observed in the crystal structure.     

Molecular complexes of sulfonamides. Part 1. 1∶1 complexes between sulfadimidine [4-amino-N-(4,6-dimethyl-2-pyrimidinyl)benzenesulfonamide] and 2- and 4-aminobenzoic acids

The crystal and molecular structures of the 11 complexes sulfadimidine·2-aminobenzoic acid (I) and sulfadimidine·4-aminobenzoic acid (II) are described and compared with known structures containing sulfadimidine. In each complex, molecular association is maintained by one N-HO hydrogen bond, and one O-HN hydrogen bond involving the imino N and one pyrimidinyl N atom of sulfadimidine and the two carboxyl O atoms of the aromatic acid. The conformation of the sulfadimidine molecule inII is unusual for anN ¹-substituted arylsulfonamide. Molecular dimensions for the complexed aminobenzoic acids are virtually the same as those reported for the free acids. Partial correlation between carboxylic acid strengths and the hydrogen bonded NO distances is observed in sulfadimidine complexes of this type.     

Crystal structure of a nucleoside analog: 2′,3′-dideoxy-3′-fluoro-5-bromocytidine

The title compound crystallizes in the orthorhombic space groupP2₁2₁2₁ witha=5.084(1),b=14.322(3),c=16.065(2)Å,Z=4. The structure was solved by the heavy atom method and refined by full-matrix least-squares calculations to a finalR value of 0.033 for 1106 unique observed reflections. The N-glycosidic torsion anglex has a value of –153.7(4)°, in the anti-range. The sugar pucker is²T₃ withP=175(1)° and=30(1)°. The C4-C5 conformation is + sc with =46.7(7)°. The structure is stabilized by N-HN, N-HO and O-HO hydrogen bonds and C-HO close contacts.     

Cooperative C≡C-H⋯O-H⋯O hydrogen bonding in a crystalline alkynol

In the X-ray crystal structure of the alkynol 5-hydroxy-5-(prop-2-ynyl)-10-methyl-¹⁽⁹⁾-octalin-2-one [C₁₄H₁₈O₂, Pca2 ₁, a = 13.559(1), b = 7.960(2), c = 21.748(3) Å], the hydroxyl and propynyl groups form a hydrogen bond chain C---C-HO-HO which is supposed to be a cooperative arrangement. Quantum chemical calculations estimate cooperativity enhancement within the array to be 0.4 kcal/mol, which is only a small (but recognizable) effect.     

Molecular structure and some reactivity aspects of 2,6-diamino-4(3H)-pyrimidinone monohydrate

Crystals of C₄H₆N₄O·H₂O are orthorhombic:Pbca,a=16.721(2),b=4.242(1),c=18.293(2)Å,Z=8. The structure has been solved by direct methods and refined by full-matrix least-squares techniques toR=0.046 for 1252 unique reflections. The structure consists of approximately planar molecules of the 3(H)4-one tautomer. Delocalization of the ring and the C=O-electrons, and conjugation of the lone-pair electrons of the amine groups with the pyrimidinone nucleus are observed. The molecules are connected by O-HO, N-HN, and N-HO hydrogen bonds. The molecular structure clarifies the chemical properties of the compound.     

Structural studies of some o-substituted S-phenyl thiobenzoates. I. Crystal structure of S-phenyl o-chlorothiobenzoate and S-phenyl o-bromothiobenzoate

Structural characteristics ofS-phenylo-chlorothiobenzoate (I) andS-phenylo-bromothiobenzoate (II) have been investigated by single crystal X-ray diffraction. It was shown that the crystals are isomorphous and crystallize in the monoclinic space groupP2₁ withZ=2. The unit cell parameters are:a=10.150(3),b=7.672(2),c=7.595(2) Å,=91.28(1)° for C₁₃H₉ClOS (compoundI) anda=10.141(3),b=7.764(2),c=7.653(2) Å,=90.14(3)° for C₁₃H₉BrOS (compoundII). The structures were solved by heavy-atom methods and refined by full-matrix least-squares, from room-temperature data collected with a Philips PW 1100 diifractometer, to conventionalR factors of 0.056 forI and 0.044 forII. The structures consist of independent molecules held together by intermolecular interactions. Molecular packing is influenced by the presence ofo-substituted Cl or Br atoms. The Cl atoms in structureI as well as the Br ones in structureII are directed to the centers of the pi-electronic system of theo-substituted phenyl rings belonging to the neighboring molecules. The six ClC and BrC distances range from 3.651(10) to 3.869(9) Å and from 3.644(6) to 3.890(6) Å, respectively. The C1 (or Br) atom is additionally directed towards the two carbon atoms (C3 and C4) in anothero-substituted phenyl ring, the C1lC and BrC distances being 3.786(9) and 3.849(10) Å inI and 3.727(6) and 3.881(6) Å inII. The torsion angle C6-C7-S-C8 is-170.2(7)° inI and 168.6(4)° inII. The angles between the planar O-C7-S central fragment of the molecule, on the one hand, and theo-substituted phenyl ring, on the other, are 113.9(3)° in I and 110.9(2)° inII. The corresponding values for the angles between the O-C7-S fragment and the nonsubstituted phenyl ring are 115.8(3)° and 114.3(2)° in compoundsI andII, respectively.     

Two acetylamino derivatives of 2,4-bis(trichloromethyl)-1,3-benzdioxin showing different types of hydrogen bonding: (a) (C13C)CH⋯O=C and (b) N-H⋯O=C

8-Acetylamino-6-methyl-2,4-bis(trichloromethyl)-1,3-benzdioxin, (I), is monoclinic,P2₁/c,a=15.174(4),b=11.977(7),c=9.911(3)Å,=99.72(2)°. 6-Acetylamino-2,4-bis(trichloromethyl)-1,3-benzdioxin, (II), is monoclinic,P2₁/_n,a=5.927(4),b=40.623(1),c =7.120(3)Å,=91.39(4)°. In compound (I) the imino hydrogen atom is locked in an intramolecular hydrogen bond to the proximate oxygen atom of the heterocyclic ring and is not available for intermolecular hydrogen bonding. Instead the weakly acidic hydrogen atom [Cl₃C-C(2)]H takes part in a hydrogen bond to the carbonyl oxygen atom in another molecule. In compound (II) a normal intermolecular hydrogen bond of the type N-HO=C occurs. The 6-acetylam-ino group is twisted about the (C_Ar-N) bond such that the angles NHO=C, C_ArH_ArO=C, NHOH_ArC_Ar, at the carbonyl oxygen group total 360° (where NH is in the related molecule). The packing in both compounds takes the form of infinite chains and in compound (II) partial overlap of the aromatic ring and the acetylamino group, with very little offset, also occurs.     

Crystal and molecular structure ofp-aminobenzene sulfonacetamide sodium [sulfacetamide sodium] monohydrate

The crystal and molecular structure ofp-aminobenzene sulfonacetamide sodium, C₈H₉N₂NaO₃S·H₂O, an important substituted sulfa drug, has been determined from diffractometric data using MoK radiation. The crystals are monoclinic, witha=6.614(2),b=23.788(6),c=7.012(2) Å,=103.13(2)°, and space groupP2₁/c. The structure was solved by the heavyatom method, and refined by full-matrix least squares to a finalR value of 0.040 with 1435 unique reflections. In packing, the molecules form dimers through pairs of N-HN and N-HO hydrogen bonds. The molecules are further stabilized by O-HO and O-HN hydrogen bonds.     

Cl⋯π(Ar), Cl⋯Cl,and other intermolecular interactions in the crystal structure of 8-nitro-6-methyl-2-trichloromethyl-4-dichloromethylene-1,3-benzodioxin

Crystals of the title compound are monoclinic,P2₁,a=9.791(4),b=7.129(3),c=10.428(3)Å,=91.84(3)°,V=727.50ų,Z=2. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by full matrix least squares to a finalR value of 0.045 using 2466 reflections. The molecules form stacks along theb axis of the formA, B, A, B(A=dichloromethylene group; B=aromatic ring in the molecule at –x, 1/2+y, –z to the molecule atx, y, z containing A). Cl(Ar),, ClCl, ClO(N), (Cl₃C)HO intermolecular interactions are also present. An inverse correlation between the (C)ClCl(C) distance and the difference in the corresponding pairs of C-ClCl angles is observed and is interpreted in terms of incipient nucleophile: electrophile attack.     

C-H⋯π(Ar)⋯Cl-C,C-Cl⋯π(Ar), Cl⋯Cl and other interactions in the crystal structure of 6-benzoyl-2,4-bis(trichloromethyl)-1,3-benzdioxin

The title compound is monoclinic,P2₁/n,Z=4,a=9.934(1),b=18.399(2),c=11.098(2)Å, =111.08(1)°. The molecule can conveniently be visualized as a benzophenone molecule with one of the aromatic rings fused to a 1,3-dioxin ring which adopts a distorted envelope conformation withcis-trichloromethyl groups substituted at positions 2 and 4. An interaction, observed for the first time, involves a hydrogen atom and a chlorine atom from opposite sides of the same aromatic ring to give C-H-(Ar)Cl-C. The parameters are Hring-centroid 2.63 A, Clring centroid 3.41 Å, Hring-centroidCl 167°, C-Hring centroid 159°, C-Clring centroid 150.2°. The (Ar) system is that of the unfused aromatic ring. A second (Ar) Cl-C interaction occurs but this time with the (Ar) system of the fused aromatic ring. The ClCl and ClO(=C) interactions form the familiar zig-zag pattern which has been noted for many chloroaromatic compounds.     

Crystal structure of a nucleoside analogue, 2′,3′-dideoxy-3′-fluoro-5-chlorocytidine

The title compound, 1-(2,3-dideoxy-3-fluoro--d-erythro pentofuranos-1-yl)-5-chlorocytosine, crystallises in the orthorhombic space groupP2₁2₁2₁ witha=5.142(1),b=14.177(2),c=15.721(2) Å,Z=4. The crystal structure was solved by the heavy atom method and refined by full-matrix least-squares method to a finalR value of 0.031 for 1629 unique observed reflections. The N-glycosidic torsion angle is –156.1(2)° and the sugar moiety is anti to the cytosine base. The sugar pucker is ₂ ³ T withP=178.2(1)° and=31(1)°. The atom 05 is in a +sc conformation with respect to the furanose ring. The molecular packing in the crystal is stabilized by N-HN, N-HO, O-HO hydrogen bonds and C-HO close contacts.     

Crystal structure and IR spectra of the molecular complex of 5,6,7,8-tetrahydroquinoline with pentachlorophenol

The crystal structure of the molecular complex of 5,6,7,8-tetrahydroquinoline with pentachlorophenol (THQ PCP) has been solved by direct methods and refined toR=0.040 for 1981 nonzero independent reflections. The O-HN hydrogen bridge is characterized by a 2.602(4) ÅON distance. The broad protonic absorption spread in the 500–3000 cm^–1 range, with two intense submaxima at 900 and 2380 cm^–1, shows relatively strong hydrogen bonds.     

Crystal structure of a nucleoside analog, 2′,3′-dideoxy-3′-azido-5-chlorocytidine

The title compound, l-(2,3-dideoxy-3-azido--D-erythro pentofuranos-1-yl)-5-chlorocytosine, crystallizes in the orthorhombic space groupP2₁2₁2₁ witha=5.840(1),b=13.780(1),c=15.396(2)Å,Z=4. The structure was solved by direct methods and refined by full-matrix least-squares calculations to a finalR value of 0.033 for 1688 unique observed reflections. The N-glycosidic torsion angle has a value of –160.8(1)°, in the and range. The sugar pucker is ₂ ³ T withP=180(1)° and=34(1)°. The C4–C5 conformation is +sc with =50.8(2)°. The azido group is nonlinear and oriented trans to the C3–C4 bond. The molecular packing in the crystalline space is stabilized by N-HN, N-HO, O-HO hydrogen bonds and C-HO close contacts.     

Crystal structure of 1,3-(N,N′-benzamide)-2-methyl-1-pentene

Crystals of the title compound are monoclinic (C20H22N2O2): space groupP2₁/n,a=11.800(3),b=13.820(2),c=11.004(3) Å,=92.74(3)°. The structure was solved by direct methods and refined by block-matrix least-squares procedure to giveR=0.078 andRw=0.076 for 1960 reflections above 3(I). The two amide groups are not coplanar with respect to their benzene rings. An intramolecular N-HO hydrogen bond was found in the molecules which are joined in chains by other strong N-HO hydrogen bonds.     

Hydrogen bonding in 2-hydroxy((di)thio)benzoates. I. X-ray structures of 2,6-dimethylpiperidinium salts

X-ray structural data are reported for 2,6-dimethyl-piperidinium-2-hydroxybenzoate (C₁₄H₂₁NO₃, orthorhombic,P2₁2₁,2₁, (19);a=7.983(1)Å,b=12.680(2)Å,c=13.838(2)Å;Z=4;R=0.042) and for two polymorphs of 2,6-dimethylpiperidinium-2-hydroxythiobenzoate (C₁₄H₂₁NO₂S), an-form (monoclinic,P2₁/n (14);a=8.005(4)Å,b=22.150(2)Å,c=8.672(4)Å,=101.91(6)°;Z=4;R=0.059) with an intramolecular O-HS hydrogen bond, and a-form (orthorhombic,P2₁2₁2₁ (19);a=8.188(1)Å,b=14.781(2)Å,c=24.163(4)Å;Z=8;R=0.15) with an intramolecular O-HO hydrogen bond. The intra-and intermolecular hydrogen bond patterns are discussed, including the literature data of 2,6-dimethylpiperidinium-2-hydroxydithiobenzoate.     

Crystal structure of 4,6-dinitro-1-(5-tetrazolyl)-1H-indazole trihydrate

The title compound, C₈H₄N₈O₄·3H₂O, crystallizes in space groupP¯1 with cell constantsa=7.022(1),b=9.507(2),c=10.906(2) Å,=84.99(1),=71.89(1),=72.56(1)°,Z=2, andV _c =660.2 ų. The structure was solved by direct methods using diffractometer data and was refined by full-matrix least-squares methods to anR value of 0.060 for 2112 observed reflections. The molecule, consisting of a phenyl ring fused to a pyrazole ring with a tetrazole ring connected to it equatorially, is planar except for the N(7) nitro-group oxygen atoms. The structure is stabilized by a three-dimensional network of O-HO, O-HN, and N-HO hydrogen bonds through the water molecules.